It is known to produce certain hydrofluoroolefins (HFOs) by the catalytic dehydrochlorination of certain hydrochlorofluorocarbons. For example, co-pending U.S. Patent Publication 2005/0090698, which is assigned to the assignee of the present invention and which is incorporated herein by reference, discloses processes involving the following reaction:

This publication indicates that these reactions may proceed by thermal decomposition, either in the presence or the absence of catalyst. With respect to the use of catalysts, this publication indicates that suitable catalysts include transition metal halides and oxides in general, and mentions specifically FeCl2, FeCl3, NiCl2 and CoCl2.
Among the halogenated olefins, tetrafluoropropenes (including HFO-1234ze) are known to be useful in numerous applications. For example, U.S. patent application Ser. No. 10/694,273, which is assigned to the assignee of the present invention and incorporated herein by reference, discloses the use of HFO-1234ze (CF3CH═CFH) as a refrigerant with low global warming potential and also as a blowing agent for use in connection with the formation of various types of foams. In addition, CF3CH═CFH can also be functionalized to variety of compounds useful as intermediates for making industrial chemicals.
Applicants have come to recognize that many of the current and prior processes for producing halogenated olefins, and in particular tetrafluorinated propene, produce a mixture of olefins which includes, in addition to the desired hydrofluorinated olefins, a substantial proportion of olefins that have fluorine and chlorine substituents. As a result, applicants have discovered a need for processes which are capable of forming hydrofluorinated olefins with a high degree of conversion and selectivity.